At least 11 people have been killed in violence against abortion providers in the U.S. since 1993, according to the National Abortion Federation. Here are some details of those attacks:

March 10, 1993: Dr. David Gunn is shot to death outside an abortion clinic in Pensacola, Florida, becoming the first U.S. doctor killed during an anti-abortion demonstration. Michael Griffin is convicted and sentenced to life in prison.

July 29, 1994: Dr. John Bayard Britton and a volunteer bodyguard are slain outside another clinic in Pensacola. Barrett’s wife, June, is wounded. Paul Hill, 40, a former minister and anti-abortion activist, confesses and cites Griffin as an inspiration. Hill is convicted of murder and executed in 2003.

Dec. 30, 1994: John Salvi opens fire with a rifle inside two Boston-area abortion clinics, killing two receptionists and wounding five others. Sentenced to life without parole, he kills himself in prison in 1996.

Jan. 29, 1998: A bomb explodes just outside a clinic in Birmingham, Alabama, killing an off-duty police officer and wounding several others. Five years later, suspect Eric Robert Rudolph is captured in North Carolina. He admits to bombing the Birmingham clinic, another clinic and a gay bar outside Atlanta, and Centennial Olympic Park, a gathering spot for the 1996 Summer Games, an attack that killed one bystander and injured more than 100. Rudolph is serving multiple life sentences at the federal Supermax prison in Florence, Colorado, near Colorado Springs.

Oct. 23, 1998: Dr. Barnett Slepian is fatally shot in his home in a suburb of Buffalo, New York. Militant abortion opponent James Kopp is convicted of the murder in 2003 and sentenced to 25 years to life in prison. He is also convicted of violating the federal Freedom of Access to Clinic Entrances Act and sentenced to life in prison.

May 31, 2009: Prominent late-term abortion provider Dr. George Tiller is shot and killed in a church in Wichita, Kansas, where he was serving as an usher; Tiller had been shot leaving his clinic 16 years earlier but survived. Scott Roeder confesses and is found guilty of murder and other counts. He is sentenced to life in prison with the possibility of parole after 50 years, but has that sentence vacated after a U.S. Supreme Court ruling. A new jury will decide how long he must serve before he is eligible for parole.

Nov. 27, 2015: A gunman kills a police officer and two people accompanying friends to a Planned Parenthood clinic in Colorado Springs. Nine others are wounded. Robert Lewis Dear, who has acknowledged being the shooter, tells investigators he drew inspiration from Hill, the killer in the 1994 Pensacola attack.